1. Clang Plugins working group
David Poliakoff

2. Use cases Static analysis Code instrumentation
Extract control flow graph
How are STL containers used (push_back(), fixed-size/dynamic etc.)

3. Compiler plugins Clang plugins vs. llvm passes Other compilers
For source code / IR: clang plugins
For LLVM assembly: llvm passes
Both can do loop analysis
Pass info from clang to llvm through artifacts
Other compilers
gcc: Undocumented plugin interface
Intel / XL: good luck
Nvidia: run away
Can use source-to-source compilation from clang
Vs. ROSE etc.
ROSE has easier source-code insertion
Clang has bigger user base

4. How to write a clang plugin
Find source locations for patterns of interest with clang-query
E.g. match forStmt(hasDescendant(declRefExpr()))
Respects defs and includes in compile_commands.json
Can be created with Cmake, bare make
Use arcane compiler knowledge
Implement AST visitors
Visits AST nodes (ifs, fors, function decls, ...)
Overwrite corresponding visitor method and do stuff
Build plugin (use recipe, e.g. from Eli’s website (see Resources))
Use plugin:
clang++ -fplugin=myplugin.so source.cpp
Can also build executables with plugin functionality

5. Resources https://clang.llvm.org/doxygen
refactoring-tools